The Unipolar channels of the TMSi equipment can be used for all sorts of ExG measurements (e.g. ECG, EEG, EMG, etc.). Since TMSi systems include no hardware filters other than the obligatory anti-aliasing (well above the band of interest), one always records the raw data.
The input stage for measuring unipolar electrophysiological signals is configured as a so called reference amplifier. All signals are amplified against the average of all connected unipolar inputs. With the help of our TMSi Polybench software package all kind of montages are possible: average reference, common reference, bipolar configurations, virtual references like Wilson point or Hjorth montages, etc. The patient ground electrode is required, but it is not an active input. It is meant as a way to keep patient potential and the amplifier potential at the same level, so that the amplifiers can function.